Exit devices are commonly mounted on the interior side of doors (e.g., in large facilities or public buildings) to hold the doors in closed positions while permitting easy egress. Exit devices typically include springs that bias a pushbar toward an extended position and a latchbolt configured to extend into or otherwise engage a door frame mounted strike to secure the door. The latchbolt typically may be retracted when a pushbar is depressed by virtue of a mechanical linkage therebetween.
In some circumstances, such as emergency situations, it may be desirable to secure all openings in a building to prevent intruders from entering. Under other circumstances, it may be desirable to “dog” the exit device to hold the latchbolt in a retracted position and the pushbar in a depressed or retracted position, which allows the door to be opened from an exterior side of the door (i.e., opposite the pushbar) for an extended period of time. Such circumstances may include, for example, during normal business hours or in an environment where noise is obtrusive. By “dogging” the exit device, door users may pass through the door with minimal, if any, noise from the exit device. Various electrical and electromechanical dogging mechanisms may be used to selectively maintain the exit device in such a dogged state, thereby selectively retaining the latchbolt in the retracted position. However, many conventional dogging mechanisms have certain limitations relating, for example, to convenience, safety, and power consumption requirements.
Certain conventional dogging mechanisms are purely mechanical, and require a custodian or other authorized person to manually set the exit device to the dogged or undogged state. Such manual operation is not only time-consuming, but may also lead to dangerous situations. For example, in the event of an emergency that necessitates securing the building, such as a “lockdown” situation, the time required to manually set each exit device in the building to the undogged state may far exceed an acceptable response time.
Other conventional systems include an electrically-activated driver (e.g., a motor, solenoid, or electromagnet) which drives the pushbar to the depressed/retracted position against the biasing force of internal springs. In order to “dog” such exit devices, the driver generally must remain energized in order to counteract the springs urging the pushbar to the extended position. Such systems typically have high power consumption requirements and require a connection to line power, which may be cost-prohibitive or otherwise disadvantageous in certain situations. Additionally, even in situations in which line power is readily available, the requirement that the driver remain activated while in the dogging state may result in significant or excessive amounts of power being used by the exit device.
In certain circumstances, a particular exit device may include one or more sensors to confirm, for example, that a door is in position (closed). However, such sensor data is typically not provided to an access control or security system, which requires that a custodian or other authorized person tour the facility to confirm that each door is closed and secure.
Certain exit devices may be provided with two or more electronic components (e.g., sensors, controllers, visual indicators, and electromechanical actuators) in electrical communication with one another via a set of wires. When the components are spaced apart from one another, installation of such components may require routing the wires along at least a portion of the length of the exit device. Current approaches to such wire routing typically take one of two forms, each of which has certain limitations. A first approach involves routing between the base plate and the floor of the channel member to which the base plate is mounted. However, this approach typically limits the number of wires that can be run, typically requires the exit device to be disassembled to add or remove wires, and can damage wires as the baseplate is reinserted into the channel member. A second approach involves using wire ties to hold the wires in the correct position as the wires are routed around moving parts in the drive assembly. This approach can be difficult and time-consuming, and if done improperly, may result in the wires being damaged by the moving components during operation of the exit device. Given the limitations of the current approaches to wire routing, it can be difficult to upgrade or otherwise retrofit an existing exit device in the field. As a result of this difficulty and the attendant costs, many property managers are discouraged from adapting to changes in security needs.
As is evident from the foregoing, many conventional dogging mechanisms, and exit device systems generally, have various limitations. For these reasons among others, a need remains for further improvements in this technological field.